The frigid, barren expanses of glaciers may not be as hostile to life as long thought—bizarre creatures have been discovered thriving inside mysterious balls of moss called “glacier mice.” A pebble serves as the anchor, with moss growing around it.

European researchers had wondered if these habitats harbored other organisms, and they decided to look inside. To their surprise, they discovered three types of microscopic animals: tiny worms, springtails, and water bears. “Traditionally glaciers have been thought of as inhospitable to life,” says Nicholas Midgley, a glaciologist at Nottingham Trent University who published the findings in Polar Biology.

“But now there is a lot of interest in life in extreme habitats.” The fluffy moss acts like insulation, protecting the invertebrates. Now the researchers are setting out to discover how these creatures colonize glacier mice in the first place. Says Midgley, “Our suspicion is that the animals are being blown by the wind and trapped by the moist surface of the moss.”